CALGARY -- A third straight loss left Canada's Kerri Einarson on the ropes after the opening weekend of round-robin play at the LGT World Women's Curling Championship.

It's still quite early but a podium appearance looked like a longshot after the team's latest defeat, a 7-6 decision to the United States in a game where Einarson threw a woeful 54 per cent.

"I'm a little disappointed in myself," Einarson said. "I wasn't very sharp out there. I had some opportunities that I missed. My girls played well and I just missed a few key shots."

Normally a powerhouse at major curling events, Canada has struggled to a 1-4 record at the Markin MacPhail Centre. Einarson, who was off for the evening draw, was in a three-way tie for 11th place in the 14-team field, ahead of only curling minnow Estonia.

A significant turnaround will be needed just to make the top-six cut for the playoffs. The same cutline will be used to determine country berths for the 2022 Beijing Olympics.

Einarson said she's trying to stay positive and learn as she goes, but her confidence seemed sapped on a post-game video conference with reporters. The emotional toll was evident, her voice cracking at times.

"It's mentally draining," she said. "It's a long week."

"I would say we've got eight more to go and we're going to build on it," ever-optimistic coach Heather Nedohin quickly added.

Canada has little wiggle room as it looks ahead and tough matchups still await.

Olympic silver medallist EunJung Kim of South Korea is on tap Monday and former world champion Eve Muirhead of Scotland is up on Tuesday.

Einarson, third Val Sweeting, second Shannon Birchard and lead Briane Meilleur are already moving close to must-win territory.

"This is our first time being on the world stage and being put in this position," Einarson said. "I know that we're a great team and we fight to the bitter end.

"We'll continue doing that (while) wearing this Maple Leaf with pride."

The Americans had their struggles too but were in control late in the game. Einarson flashed a stone in the fourth end and wrecked on a guard in the fifth to miss out on multiple points.

American skip Tabitha Peterson made a nice pick to score a deuce in the eighth end for a 7-3 lead. Einarson rebounded with a pair in the ninth but the U.S. sealed the victory with a takeout of the second shot stone in the 10th end.

"The girls are giving everything they've got," Nedohin said. "Sometimes it just doesn't turn out on the scoreboard to the way they're playing with passion."

Sweeting nearly saved ends a few times and the Canadian front end was steady too. Like Einarson, Peterson struggled too - shooting just 55 per cent herself - but Einarson made only half of her draws and never found a consistent rhythm.

Next up is a morning game against a shorthanded German side skipped by Daniela Jentsch. The South Korea matchup is set for the afternoon.

"They're going to win the next one and then they're going to keep climbing," Nedohin said. "I want to know that they believe they can, and they will."

The morning draw was postponed Sunday and competition later resumed without television coverage after members of the event's broadcast staff tested positive for COVID-19.

In an email to The Canadian Press, World Curling Federation media head Christopher Hamilton confirmed there were four positive cases. No names or additional details were provided.

The individuals were isolating in their hotel while additional testing and contact tracing takes place, the WCF said in its statement. The staffers are staying in a different hotel than athletes and competition officials.

The WCF said that all scheduled testing for athletes and competition officials returned negative results. The arena was given a deep clean and start times for the afternoon and evening draws were pushed back a half hour.

In other afternoon games, Russia's Alina Kovaleva remained unbeaten at 5-0 with an 8-6 win over Estonia's Marie Turmann. South Korea defeated Scotland 8-4 and Italy's Stefania Constantini outscored Germany 10-6.

Defending champion Silvana Tirinzoni of Switzerland and reigning Olympic champion Anna Hasselborg of Sweden were undefeated at 3-0. Scotland was alone in fourth place at 3-1 while the Americans improved to 3-2.

Television broadcasts will resume no earlier than Tuesday afternoon. The competition is part of TSN's Season of Champions coverage and is broadcast internationally by World Curling TV.

"Thanks for the good wishes," TSN broadcaster Vic Rauter said on Twitter. "We are quarantined, tested, cared for, hope to be back Tuesday, take care of yourselves and each other."

Earlier in the week, organizers cancelled the opening practice sessions after two members of the German team tested positive for COVID-19 in pre-tournament screening upon arrival in Calgary.

Practice sessions were eventually held Thursday on the eve of round-robin play. The German side was given an exemption to compete as a three-player team while players who tested positive remained in isolation.

This year's women's championship, which was relocated from Switzerland because of the pandemic, is the seventh and final curling event to be held in the spectator-free controlled environment.

The Canadian women's, men's and mixed doubles championships were followed by the men's world championship and a pair of Grand Slam events.

The men's world championship playoffs were interrupted by four participants testing positive for the coronavirus. The championship was completed April 11, however, with the WCF stating the cases were "false positives."

Those affected tested negative in subsequent screenings.

Teams are confined to the arena and the tournament hotel across the Trans-Canada Highway. They drive themselves back and forth and masks are mandatory once athletes step off the field of play.

Organizers have yet to determine when the postponed draw will be played. Playoff games are set to begin Friday night and the medal games are scheduled for May 9.

Jennifer Jones was the last Canadian skip to win this event, taking gold in 2018 at North Bay, Ont. Chelsea Carey skipped the Canadian entry in 2019 at Silkeborg, Denmark, but did not make the playoffs.

This report by The Canadian Press was first published May 2, 2021.